Catalysts for polymerization reactions



Patented July 31, 1945 l r 2,380,615

curl-so STATES PATENT OFFICE 2,880,018 ea'mus'rs ron ronnmm'za'non BEAGHONS William 1). stem and Benjamin M. o. Zwioker,

Akron,0hio,aaeignorsto'1'heB.F.

New York, N. Y., a corporation of New York\ p v v .No Drawing. soouoauonm'y ta-1m,

. serum. 444,590

14cm (cues-e419 This invention relates to the polymerization of a unsaturated organic compounds which are cap- 8 NB able oi! undergoing an'addition polymerization to E form high molecular weight linear polymers, and v particularly to the polymerization m the form or a W an aqueous emulsion of a butadiene-1,3 either s s alone or in admixture with a monomer copolynnr-crm a-mn merizable therewith. The principal object of the inventionds to provide a method for decreasing T the time-required to fleet such polymerization Many other compounds containing the same a t characteristic grouping may also be employed as We have discovered that the time required to catalysts to speed up the polymerization.

' eflect polymerization reactions may be decreased The preferred methods of practicing this inby polymerizing unsaturated organic compounds vention will be shown by the iollowing speciiic in the presence oi! a compound containing the examples which illustrate rather than limit the group invention.

-s 1 Example I --NH-&I%B' A mixture containing 12 parts by weight oi wh e R rep esents an acidic group B may be butadiene, styrene. about 20 of a any desired acidic group and mayor t 3% aqueous solution oi! an alkyl benzene sulform part of a ring structure. Groups containing ionate, 0.23 part of NmHPO4-l2H1O, 0.06 part of a doubly or triply bonded carbon atom such as l t i persul ate, and 0096mm 1 mixed higher aliphatic mercaptans with chains contain- 2 ing from 10 to 18 carbon atoms was agitated at C. The polymerization required 44 hours to or -C:-:N connected to the nitrogen either direach completion, but when 0.05 part oi thiorectLv or by a single carbon atom are preferred barbituric acid was added at the beginning oi the acidic groups. As examples of such compounds polymerization, the reaction was finished in 10' may be mentioned hours.

s Example 11 a mi-(Lisa A A mixture containing 12 parts by weight 0! l; hutadiene, 4 parts of styrene, about 20 parts of a been neutralized with sodium hydroxide,

5 0 0.23'part o! NaaHPOr12HzO, 0.06 part 01 potas- Om-i-mn-om-Ji-on slum persuliate, and 0.072 part 01 diisopropyl dixanthogen were agitated at 50 C. The Wlymeri- W zation was only 5% complete in 13 hours, but 8 40 when 0.025 part 01 thiobarb'itm'ic acid was added .8 at the beginning of the polymerization, the rej l, is action was 50% complete in 13 hours.

I The catalysts or this invention may also be em- 1 ployed in conjunction with heavy metal com- 5 5 pounds, in which, case the polymerization pro- .ceeds more rapidly than when either catalyst is 4 employed alone and the system will tolerate con- 5 E o siderably higher proportions of heavy metal. 'rhiohydmtoin s 5 1941. As therein disc osed, the term heavy metal isused to'signiiy metals which have a density greater than tour. an atomic weight greater than M II forty and a low-atomic volume (ratio of atomic 1 4% aqueous solution 0! myristic acid which had v weight to density) andconsequently appear substantially at the minimum points above an atomic weight of forty on Lothar Meyer's atomic volume curve. The metals appearing in the center positions of the long periodsof a periodic table arranged in long and short periods, and especially those which occur in the 6th to 12th positions of the long periods (considering the alkali metals to occupy the first position and all the rare earth metals to occupy a single position), that is the metals appearing in group VIII, subgroup B of groups I and 11, and subgroup A of groups VI and VII are accordingly among the metals included in the term heavy metal. The metalsof group VIII, particularly those occurring in the first long period, specifically iron, cobalt, and nickel, are preferred.

Example '11! polymerization was 30% complete in hours, but

when 0.05 part of thiobarbituric acid was added at the beginning of the polymerization, the reaction was 80% complete in 5 hours. The use or 0.05 part 01' phenylthiohydantoic acid in the above recipe also increased the rate of polymerizatioh.

Although the preferred method of polymerization is by an emulsion polymerization as set iorth in the specific examples, the catalysts herein described may be employed to accelerate the rate of polymerization in homogeneous systems in the presence or absence of solvents or diluents in-the manners well known to the prior art.

The catalysts of this invention may be employed in widely varying proportions. The use of from 0.1 to 0.5% by weight based on the poly-.

merizable materials ordinarily gives a 'pronounced catalytic elfect. Noticeable effects are produced by the use of lower concentrations. although the optimum amount for the greatest catalytic eifect is ordinarily above 0.1%. Greater amounts such as 1% or more can in general be employed, if desired, without any detrimental eflfects. Although less than 0.1% of heavy metal compound, preferably in the form of a watersoluble salt is ordinarily employed, the catalysts of this invention which form complexes with heavy metal compounds permit the use of a greater concentration of heavy metal than can be employed in-the absence of any complexiorming compound. The complex-forming compound and the heavy metal compound may be added separately to the monomers prior to or during the polymerization, or may be reacted to form a heavy metal complex before they are added to the monomers.

The catalysts ofthis invention may be employed in the polymerization of any unsaturated organic compound which contain a one group and which are capable of undergoing an addition polymerization to form a high molecular weight linear polymer, that is, a polymerhaving a molecular weight 01 at least 10,000 and a substantially linear structure. Included in this class of monomers are the butadienes-L3 such as 'outadiene-1,3, isoprene, 2,3-dimethyl butadlene, piperylene, and chloroprene; aryl oleflns such as styrene, vinyl naphthalene, and alph'achlorostyrene; acrylic and alpha-substituted acrylic acids, esters, nitriles, and amides such as acrylic acid, acrylonitrile, alpha-methacryionitrile, alpha-chloracrylonitrile, methyl acrylate, methyl methacrylate, methacrylamide; vinyl halides, esters, ethers, and ketones such as vinylidene chloride, vinyl chloride, vinyl acetate. methyl isopropenyl ketone, and methyl vinyl ether. Any of the above compounds may also be copolymerized one with another. Butadiene, for instance, may be copolymerized with one or more monomers which enter into the polymeric chains by 1,-2-addition such as acrylonitrile, styrene, methyl acrylate, etc. a

As emulsifying agents which may be employed in emulsion polymerizations may be mentioned and sodium isopropyl naphthalene sulfonate, and

salts of organic bases containing long carbon chains such as the hydrochloride of diethylaminoethyloleylamide, trimethylcetylammonium methyl sulfate, the hydrochloride of oleylamidoethyldimethylamine, and the hydrochloride of the diethylaminoethoethoxyanilide of ,oleic acid. The soaps are employed in polymerizations under basic conditions, the salts of organic bases under acid conditions, and the synthetic saponaceous inaterials under acid, alkaline, or'neutral condiions.

The polymerization may be eflected by various known initiators of polymerization such as percompounds including hydrogen peroxide, benzoyl peroxide, ammonium persulfate, potassium persulfate, and other peroxides and persaltssuch persulfates, perborates. percarbonates, and the like, as well as other types of initiators such as diazoaminobenzene, sulfur dioxide, hyposulfites, bisulfites, dipotassium diazomethane disulionate,

and triphenylmethylazobenzene. The p0lymerizauseful in connection with the polymerization of unsaturated organic compounds are within the spirit and scope of the invention as defined in the appended claims.

We claim: 1. The method which comprises polymerizing a butadiene-l,3 in aqueous emulsion in the presence of an organic compound containing a structure, said compound being selected from the class consisting of thiobarbituric acid, phenylthiohydantoic acid, trithiocyanuric acid, thiohydantoin, thioallantoin, guanylthiourea and thiobiuret.

2. The method of claim 1 further characterized in that a water-soluble heavy metal compound is present during the polymerization.

3. The method which comprises polymerizing a butadiene-1,3 in aqueous emulsion in the presence of thiobarbituric acid.

4. The method which comprises polymerizing in aqueous emulsion a mixture of butadiene and a monomer copolymerizable therewith in aqueous emulsion, in the presence of an organic compound containing a structure, said compound being selected from the class consisting of thiobarbituric acid, phenylthiohydantoic acid, trithiocyanuric acid, thiohydantoin, thioaliantoin, guanylthiourea and thiobiuret.

5. The method of claim 4 further characterized in that a water-soluble heavy metal compound is present during the polymerization.-

6. The method which comprises polymerizing in the form of an aqueous emulsion a mixture comprising butadiene and a monomer copolymerizable therewith in aqueous emulsion, in the presence of a mixture of thiobarbituric acid and a water-soluble salt of a heavy metal occurring in grgup VIII and the first long period of the periodic ta le.

7. The method which comprises polymerizing in the form of an aqueous emulsion a mixture comprising butadiene and acrylonitrile in the resence or thiobarbituric acid.

8. The method which comprises polymerizing in the form or an aqueous emulsion a mixture comprising butadiene and styrene in the presence of thiobarbituric acid.

9. The method which comprises polymerizing in aqueous emulsion a mixture comprising butadiene and acrylonitrile in the presence of phenylthiohydantoic acid.

10. The-method which comprises polymerizing,

in the form of an aqueous emulsion, a mixture of butadiene and acrylonitrile in the presence of a heavy metal complex containing a heavy metal occurring in group VIII and the first long period of the periodic table and thiobarbituric acid.

11. The method of claim 10 in which the heavy metal is iron.

12. The method of claim 10 in which iron and another heavy metal are employed.

13. The method which comprises polymerizing in aqueous emulsion a mixture of butadiene and styrene in the presence or a complex compound of a heavy metal occurring in group VIII and the first long period of the periodic table and thiobarbituric acid. I

14. The method which comprises polymerizing in aqueous" emulsion a mixture of butadiene and acrylonitrile in the presence of phenylthiohydantoic acid and a water-soluble salt of a heavy metal occurring in group VIII and the first long period of the periodic table.

WILLIAM D. STEWART. BENJAMIN M. G. ZWICKER. 

